This application claims the priority benefit of Taiwan application serial no. 92105867, filed Mar. 18, 2003.
1. Field of Invention
The present invention relates to a package structure for a microsystem. More particularly, the present invention relates to a package structure for a microsystem, which has an annular adhesive structure with an opening between the micro-mirror-mechanism and the CMOS chip.
2. Description of Related Art
For the projecting instruments, the planar images are enlarged by being projected onto the large screens, so that more persons can view the images at the same time. At the present, the projectors are commonly used for conferences or educational training in companies and schools. Furthermore, the recent model projectors can be connected directly to the notebook computers or desktop computers, for projecting the images, texts or charts. In addition, the projection television displays images on the screen by way of projection.
FIG. 1 is a display view illustrating a projecting apparatus in general. As shown in FIG. 1, the projecting apparatus 100 comprises a light source 102, front lens 104, 108, a color filter 106, a microsystem package structure 120, a lens 110 and a screen 112. Light 114 coming from the light source 102 strikes the lens 104 and is then refracted by the lens 104. Light 114, after refracted by lens 104, passes the color filter 106 and strikes the lens 108. After being refracted by the lens 108, light 114 is projected on the microsystem package structure 120. Then microsystem package structure 120 includes a CMOS chip and a plurality of micro-mirror sets. Light 114, controlled by the rotation of the micro-mirror sets, is reflected to the screen 112 through the lens 110. However, heat is generated during the operation of CMOS chip and from the focused light onto the micro-mirror sets. The generated heat will raise the temperature and increase the pressure of the system, leading to distortion or deformation of the system and inaccurate and faulty control of the light reflection path for the projecting apparatus.
The present invention provides a microsystem package structure, which can accurately control the projective locations of the light through reflection of micro-mirrors, without distortion of the micro-mirror-mechanism resulting from high pressure or temperature.
As embodied and broadly described herein, the present invention provides a microsystem package structure comprising a substrate, a chip, a micro-mechanism, a adhesive structure, a plurality of wires, an annular body and a transparent plate. The chip is attached to the substrate and electrically connected to the substrate through wires. The adhesive structure, in an annular shape, has an opening and is arranged between the chip and the carrying substrate. Since the carrying substrate is placed on the adhesive structure, an interspace is formed between the chip, the adhesive structure and the carrying substrate. The pressure inside the interspace can be balanced with the pressure outside the interspace through the opening.
The opening of the adhesive structure can be arranged in the central portion of one side of the adhesive structure or at corners of the adhesive structure. Alternatively, the adhesive structure includes a plurality of openings. The adhesive structure has a shape of a hollow tetragon, for example. The adhesive structure can further include a protrusion around the opening and on the outer side of the adhesive structure. The microsystem package structure can further includes desiccant within the closed chamber between the substrate, the annular body and the transparent plate.
In conclusion, the present invention can greatly reduce distortion of the carrying substrate, resulting from generated heat during the operation of CMOS chip and from the focused light onto the micro-mirror-mechanism. If the interspace is closed (sealed), the generated heat will heat up the interspace and the pressure of this space is increased with the elevated temperature, leading to distortion of the above carrying substrate. However, in the present invention, the interspace is connected to the chamber through the opening of the adhesive structure, the pressure of the interspace is balanced and lowered, so that distortion of the carrying substrate is prevented and the angle or position of the micromirror is well controlled. As a result, the light reflected by the micro-mirror-mechanism is precisely controlled and projected to the desired location.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.